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JOHANN ES KORSELT, OF ZIITAII, GERMANY, ASSIGNOR, BY MESNE ASSIGNMENTS, TO THE CHEMICAL FOUNDATION, INC, A CORPORATION OF DELA'W'ARE.

'PIROGESS FOR THE TREATMENT OF SILK WITH RESERVES FOR, THE PURPOSE OF INCREASING ITS STRENGTH AND ELASTICITY.

No Drawing.

To all whom it ma concern Be it known that I, JOIHANNES Konsinn, a

citizen of the Kingdtm of Saxony, Germany, residing at Zittau, in Saxony, have 5. invented certain new and useful Improvements in Processes for the Treatment of Silk with Reserves for the Purpose of Increasing Its Strength and Elasticity, of which the following is a specification;

This process relates to the treatment by reserves of silk with a view to increasing the strength and elasticity of the same. In accordance with this process silk is acted upon by organic compounds, particularly by compounds containing nitrogen or sulfur and nitrogen combined and which are soluble in water or in dilute acids and which the silk material after loading the same, for:

instance according to the tin-phosphate-silicate process. It has been ascertained that in the operation of this process those organic compounds particularly nitrogenous compounds or those containing nitrogen and sulfur, which are not volatilized by intense radiation of the rays of the sun and which cannot be removed from the silk fiber by a strong draft of air, produce the most intense and most permanent reserve action upon the silk material.

In order that the solution of the reserve 7 body may be adapted to more completely 4Q permeate the fibroin which has become swollen and therefore ordinarily less permeable after loading, and in order to prevent the reserve from depositing merely upon the peripherous layers of the fibroin, it is advisable to carry on the treatment at such temperature and for such length of time as "to insure thorough impregnation.

In order toefiect an additional fixation of the reserve body in the interior of the silk "fiber after impregnating, I may precipitate the reser e body in the interior of the fiber by means of well known reactions so as to make said reserve body insoluble or dificultly soluble, by means of which the Specification of Letters Patent.

Patented Oct. 7, 1919.

Application filed November 15, 1915. Serial No. 81,656.

durability of the protecting action of the reserve is further increased.

The substances employed according to my invention act in such a manner that they will protect silk which has been loaded by the tin-phosphate-silicate process, from beingdecomposed or oxidized by oxygen or by oxygen carriers such as tin-compounds which liberate oxygen when decomposed. Of such substances I may mention by way of example, cholin, betaine, and alkaloids generally and all those organic compounds which, when treated with loading agents, are more readily oxidized than fibroin. On the other hand, those substances which effect merely a mechanical holdingtogether of the broken down or brittle fibroin by means of their adhesive properties and which, according to their natural properties, are employed as mere sizing agents, as for instance glue, dextrin or diastaphore. are not comprised by my invention. On the contrary, the substances which are comprised by my invention are characterized by the fact that they change neither the touch nor the color and appearance of the silk fiber. Furthermore my invention does not include those organic substances which are spontaneously (lQCOl'llPOSGd by the loadingagent and in the presence of the action of sun light without forming any decomposition-products which have any practical efiiciency as protecting or reserve agents, such as urea, or thio-urea, nor volatile substances, sueh as formaldehyde, hydroxylamin, and their salts or derivates, nor such compounds as produce undesired color-reactions, such as the thio-cyanates or hydro quinone.

In carrying the process into effect I may proceed by treating the silk after loading with a five percent-solution of cholin.

I may also proceed by treating the silk after loadin with a two per cent solution of sodi'um-hippurate, then removing the liquid by centrifugal action, and depositing the hippuric acid by means of hydrochloric acid within the fiber in a dii'iicultly soluble state.

As compared with all processes heretofore known for the protective treatment of. silk a most important technical improvement is accomplished by my process on account of. the universal applicability of all organic,

soluble, non-volatile, compounds of the kind hereinbefore referred to, which are more v readily oxidized than fibroin, particularly 2. The process for the protective treat ment of silk consisting in loading the silk by the tinphOsphate-silicate method, treating the silk thus loaded with a readily soluble nitrogenous compound containing nitrogen and sulfur which will not volatilize said tin loading compound and at a temperature and for a sufiicient length of time to 'efi'ect a thorough permeation of the silk with the compound and without decomposition'of the silk fiber, and precipitating the reserve body in the interior of the silk by well. known reactions.

3. The process for the protective treatwitnesses.

ment of loaded silk, consisting in loadin the silk by the tin-phosphate-silicate metho then treating the silk thus loaded with an organic nitrogenous compound readily soluble in water which will not decompose the silk fiber, contains nitrogen and sulfur, is not volatile at an ordinary temperature and is readily oxidizable to preserve the touch, color and appearance of the silk and which will prevent deterioration of the silk by counteracting salts, and finally precipitat ing the reserve body in the interior fiber of the silk by well known reactions.

4. The process for the protective treatment of silk, consisting in loadin the silk by the tin-phosphate-silicate met 10d, then treating the loaded silk with cholin, and finally precipitating the cholin that has been added to the silk and held within the fiber thereof by well known reactions.

In testimony whereof I have hereunto set my hand in presence of two subscribing DR. JQHANNES KORSELT. Witnesses:

HENRY HASPER,

ARTHUR SGHROEDER. 

